Study on dead zone light recovery of silicon photomultipliers (SiPM) based on focon/tapered fiber arrays

To solve light loss from dead zones between Geiger-mode avalanche photodiode cells in silicon photomultipliers (SiPMs), this paper proposes a dead-zone light recovery scheme using focon/tapered fiber arrays. A microlens-like alignment method achieves precise fiber-SiPM integration. A multi-physics coupling simulation model compares light transmission and photoelectric response of original SiPM, tapered fiber-SiPM, and focon-SiPM under 13/25 μm cell sizes. Simulations show that under 300–1100 nm incident light, both structures significantly optimize SiPM performance: Tapered fibers boost average photocurrent by 70.19% and effective fill factor by 69.93% for 13 μm cells and 35.56%/33.84% for 25 μm cells. Focons show slightly lower improvements (68.77%/68.90% for 13 μm and 32.04%/30.84% for 25 μm). Neither scheme affects SiPM electrical stability. Tapered fibers excel in light recovery under small incident angles and wide bands, with applications in low-light detection (PET imaging, automotive light detection and ranging, and bioluminescence detection).